How to use "countless" in a sentence

Now this was only a young boy's bedroom, a room like countless thousands of others.

A long time had passed since his years in military intelligence, since the nights of fear in the Persian Gulf and in countless cities scattered around the Mideast and Asia

She knew from experience that fate had countless nasty tricks up its voluminous sleeve, and that was why she was scared shitless.

All I know is that during the fourteen or sixteen - or seven thousand - months that we worked together, through countless story meetings in the development executive's office, I was never sure that any of my writing confreres had read the complete novel that he or she was adapting - or understood what had been read

However, for most of the time the daily routine of work, food, drink and sleep went on as it had done for countless years.